As air conditioners which perform heating and cooling, there are known air conditioners which change an operation frequency of a compressor when adjusting heating and cooling performance. Such air conditioners control an rpm of a motor which drives the compressor through inverter control.
As power supply devices which perform inverter control, there are known power supply devices which perform pulse amplitude modulation (PAM). In PAM control, alternating voltage is converted into direct voltage by a rectifier circuit, and thereafter, is converted into desired voltage by a booster circuit. The booster circuit is composed of a reactor element, a switching element, a diode, a capacitor, and the like.
The booster circuit controls a ratio (duty ratio) of ON time of the switching element. Accordingly, it is possible to control a waveform and a current value of an alternating current input to the rectifier circuit provided at a preceding stage, which enables an improvement in power factor and a reduction in high frequency current, as well as control of direct voltage.
Note that the generation of at least two or more PAM pulses in a half period of a power supply frequency (increase in the number of pulses) enables a further improvement in power factor and a further reduction in high frequency current. The PAM control is referred to as multi-pulse PAM control.
As a power supply device which performs PAM control, there is, for example, one described in Patent Document 1.
Patent Document 1: Japanese Patent Application Laid-Open No. 10-330731